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See detailHigh-Resolution GC Coupled to High-Resolution MS in the Analysis of Dioxins and Related Substances, Principles and Applications
Eppe, Gauthier ULg; De Pauw, Edwin ULg; Focant, Jean-François ULg

in Niessen, W. M. A. (Ed.) The Encyclopedia of Mass Spectrometry, Volume 8, Hyphenated Methods (2006)

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See detailHigh-resolution gene maps of horse chromosomes 14 and 21: Additional insights into evolution and rearrangements of HSA5 homologs in mammals.
Goh, Glenda; Raudsepp, T; Durkin, Keith ULg et al

in Genomics (2007), 89

High-resolution physically ordered gene maps for equine homologs of human chromosome 5 (HSA5), viz., horse chromosomes 14 and 21 (ECA14 and ECA21), were generated by adding 179 new loci (131 gene-specific ... [more ▼]

High-resolution physically ordered gene maps for equine homologs of human chromosome 5 (HSA5), viz., horse chromosomes 14 and 21 (ECA14 and ECA21), were generated by adding 179 new loci (131 gene-specific and 48 microsatellites) to the existing maps of the two chromosomes. The loci were mapped primarily by genotyping on a 5000-rad horse × hamster radiation hybrid panel, of which 28 were mapped by fluorescence in situ hybridization. The approximately fivefold increase in the number of mapped markers on the two chromosomes improves the average resolution of the map to 1 marker/0.9 Mb. The improved resolution is vital for rapid chromosomal localization of traits of interest on these chromosomes and for facilitating candidate gene searches. The comparative gene mapping data on ECA14 and ECA21 finely align the chromosomes to sequence/gene maps of a range of evolutionarily distantly related species. It also demonstrates that compared to ECA14, the ECA21 segment corresponding to HSA5 is a more conserved region because of preserved gene order in a larger number of and more diverse species. Further, comparison of ECA14 and the distal three-quarters region of ECA21 with corresponding chromosomal segments in 50 species belonging to 11 mammalian orders provides a broad overview of the evolution of these segments in individual orders from the putative ancestral chromosomal configuration. Of particular interest is the identification and precise demarcation of equid/Perissodactyl-specific features that for the first time clearly distinguish the origins of ECA14 and ECA21 from similar-looking status in the Cetartiodactyls. [less ▲]

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See detailHigh-Resolution Limb Observations of Proton Aurora
Chua, D. H.; Dymond, K. F.; Budzien, S. A. et al

Conference (2003, December 01)

The interaction of precipitating protons in the upper atmosphere involves charge exchange, ionization, elastic and inelastic collisions, and the deposition of energy from the bottom of the F-region to the ... [more ▼]

The interaction of precipitating protons in the upper atmosphere involves charge exchange, ionization, elastic and inelastic collisions, and the deposition of energy from the bottom of the F-region to the D-region of the ionosphere. These processes and the transport of incident protons through this range of altitudes has been described through a variety of modeling techniques but there has been a dearth of altitude-resolved observations of proton precipitation with which to validate such models. We present new limb observations of Doppler-shifted Lyman-α proton aurora emissions obtained by the High-resolution Ionospheric and Thermospheric Spectrograph (HITS) aboard the Advanced Research and Global Observation Satellite (ARGOS) that fill this niche. HITS performs limb scans that include tangent altitudes between 90 km and 400 km with approximately 5 km vertical resolution. The Doppler shifts of the proton aurora Lyman-α emissions are measured with 1.5 Angstrom resolution and are used to infer mean energies of the incident protons as a function of altitude. Observed energy-range (dE/dz) relations are compared to those predicted by a Monte Carlo simulation of proton transport in the upper atmosphere. [less ▲]

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See detailHigh-resolution measurements and modelling of the Cape Ghir upwelling filament during the CAIBEX survey
Troupin, Charles ULg; Sangrà, Pablo; Arístegui, Javier et al

Poster (2010, April 26)

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See detailHigh-resolution measurements of an upwelling filament during the CAIBEX survey
Troupin, Charles ULg; Sangrà, Pablo; Arístegui, Javier et al

Poster (2011, May 02)

Upwelling filaments have been studied for several years. We aim to explain the general process in terms of potential vorticity: An injection of positive vorticity north of the Cape forces the jet to turn ... [more ▼]

Upwelling filaments have been studied for several years. We aim to explain the general process in terms of potential vorticity: An injection of positive vorticity north of the Cape forces the jet to turn offshore, in virtue of the principle of vorticity conservation. The Regional Ocean Modeling System (ROMS) is implemented in the Cape Ghir region, with horizontal resolution lower than 1 km. A set of process-oriented experiments has been designed in order to determine the mechanisms at the origin of the filament. [less ▲]

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See detailHigh-resolution micro-CT as a tool for 3D surface roughness measurement of 3D additive manufactured porous structures
Kerckhofs, Greet ULg; Pyka, Grzegorz; Moesen, Maarten et al

in Proceedings iCT 2012 (2012)

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See detailHigh-Resolution Microfocus X-Ray Computed Tomography for 3D Surface Roughness Measurements of Additive Manufactured Porous Materials
Kerckhofs, Greet ULg; Pyka, Grzegorz; Moesen, Maarten et al

in ADVANCED ENGINEERING MATERIALS (2013), 15(3), 153-158

Since commercially available profiling systems fail when determining the surface roughness of porous materials, we propose a novel protocol for surface roughness quantification of 3D additive manufactured ... [more ▼]

Since commercially available profiling systems fail when determining the surface roughness of porous materials, we propose a novel protocol for surface roughness quantification of 3D additive manufactured porous structures based on high-resolution microfocus X-ray computed tomography (micro-CT) images. It allows to non-destructively assess the roughness of these porous materials at the outer surface as well as inside the structure. The noise in the images and the spatial image resolution both have a significant effect on the accuracy of the micro-CT-based roughness measurements. Comparing the roughness parameters of flat substrates determined both with commercially available (optical and contact) profiling systems and the micro-CT-based roughness measurement protocol shows that micro-CT can be applied accurately and in a robust manner for surface roughness quantification of 3D additive manufactured porous materials with a micro-scale roughness. Depending on the dimensions of the roughness, the micro-CT acquisition parameters, i.e., frame averaging and spatial image resolution, need to be fine-tuned. Submicron-scale roughness can currently not be quantified. [less ▲]

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See detailHigh-resolution modelling of the Antarctic surface mass balance, application for the 20th, 21st and 22nd centuries
Agosta, Cécile ULg; Favier, Vincent; Krinner, Gerhard et al

Poster (2013, April)

Although areas below 2000 m above sea level (a.s.l.) cover 40% of the Antarctic grounded ice-sheet, they represent about 75% of the surface mass balance (SMB) of the continent. Because the topography is ... [more ▼]

Although areas below 2000 m above sea level (a.s.l.) cover 40% of the Antarctic grounded ice-sheet, they represent about 75% of the surface mass balance (SMB) of the continent. Because the topography is complex in many of these regions, SMB modelling is highly dependent on resolution, and studying the impact of Antarctica on the fu- ture rise in sea level requires high resolution physical approaches. We have developed a new, low time consuming, physical downscaling model for high-resolution (15 km) long-term SMB projections. Here, we present results of our SMHiL (surface mass balance high-resolution downscaling) model, which was forced with the LMDZ4 atmo- spheric general circulation model to assess SMB variation in the 21st and the 22nd centuries under two different scenarios. The higher resolution of SMHiL reproduces the geographical patterns of SMB better and induces a significantly higher averaged SMB over the grounded ice-sheet for the end of the 20th century. Our comparison of more than 2700 quality-controlled field data showed that LMDZ4 and SMHiL fit the observed values equally well. Never- theless, field data below 2000 m a.s.l. are too scarce to settle SMHiL efficiency. Measuring the SMB in these undocumented areas is a future scientific priority. Our results suggest that running LMDZ4 at a finer resolution may give a future increase in SMB in Antarctica between 15% to 30% higher than its standard resolution. Future changes in the Antarctic SMB at low elevations will result from the conflict between higher snow accumulation and runoff. For this reason, developing a downscaling model was crucial to represent processes in sufficient detail and correctly model the SMB in coastal areas. [less ▲]

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See detailHigh-resolution modelling of the Antarctic surface mass balance, application for the twentieth, twenty first and twenty second centuries
Agosta, Cécile ULg; Favier, Vincent; Krinner, Gerhard et al

in Climate Dynamics (2013), 41(11-12), 3247-3260

About 75% of the Antarctic surface mass gain occurs over areas below 2000 m asl, which cover 40% of the grounded ice-sheet. As the topography is complex in many of these regions, SMB modelling is highly ... [more ▼]

About 75% of the Antarctic surface mass gain occurs over areas below 2000 m asl, which cover 40% of the grounded ice-sheet. As the topography is complex in many of these regions, SMB modelling is highly dependent on resolution, and studying the impact of Antarctica on the future rise in sea level requires physical approaches. We have developed a low time consuming, physical downscaling model for high-resolution (15 km) long-term surface mass balance (SMB) projections. Here, we present results of this model, called SMHiL (surface mass balance high-resolution downscaling), which was forced with the LMDZ4 atmospheric general circulation model to assess SMB variation in the 21st and the 22nd centuries under two different scenarios. The higher resolution of SMHiL better reproduces the geographical patterns of SMB and increase significantly the averaged SMB over the grounded ice-sheet for the end of the 20th century. A comparison with more than 3200 quality-controlled field data shows that LMDZ4 and SMHiL compare the observed values equally well. Nevertheless, field data below 2000 m asl are too scarce to efficiency show the interest of SMHiL and measuring the SMB in these undocumented areas should be then a future scientific priority. Our results suggest that running LMDZ4 at a finer resolution (15km) may give a future increase in SMB in Antarctica about 30% higher than by using its standard resolution (60 km) due to higher increase in precipitation in the coastal areas at 15 km. However, a part (~ 15%) of these discrepancies could be an artefact from SMHiL since it neglects the foehn effect and then likely overestimates the precipitation increase. Future changes in the Antarctic SMB at low elevations will result from the conflict between higher snow accumulation and runoff. For this reason, developing downscaling models is crucial to represent processes in sufficient detail and correctly model the SMB in the coastal areas. [less ▲]

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See detailHigh-resolution non-destructive 3D quantitative imaging of the cartilage subarchitecture
Kerckhofs, Greet ULg; Sainz, Julie; Wevers, Martine et al

Conference (2012)

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See detailHigh-resolution non-destructive 3D quantitative imaging of the cartilage subarchitecture
Kerckhofs, Greet ULg; Sainz, Julie; Wevers, Martine et al

Conference (2012)

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See detailHigh-Resolution Optical and Near-Infrared Imaging of the Quadruple Quasar RX J0911.4+0551
Burud, I.; Courbin, F.; Lidman, C. et al

in Astrophysical Journal (1998), 501

We report the detection of four images in the recently discovered lensed QSO RX J0911.4+0551. With a maximum angular separation of 3."1, it is the quadruply imaged QSO with the widest known angular ... [more ▼]

We report the detection of four images in the recently discovered lensed QSO RX J0911.4+0551. With a maximum angular separation of 3."1, it is the quadruply imaged QSO with the widest known angular separation. Raw and deconvolved data reveal an elongated lens galaxy. The observed reddening in at least two of the four QSO images suggests differential extinction by this lensing galaxy. We show that both an ellipticity of the galaxy ( epsilon _{{min}}=0.075 ) and an external shear ( gamma _{{min}}=0.15 ) from a nearby mass have to be included in the lensing potential in order to reproduce the complex geometry observed in RX J0911.4+0551. A possible galaxy cluster is detected about 38" from RX J0911.4+0551 and could contribute to the X-ray emission observed by ROSAT in this field. The color of these galaxies indicates a plausible redshift in the range of 0.6-0.8. [less ▲]

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See detailHigh-resolution optical spectroscopy of Plaskett's star
Linder, Natacha ULg; Rauw, Grégor ULg; Martins, Fabrice et al

in Astronomy and Astrophysics (2008), 489(2), 713-723

Context. Plaskett's star (HD 47 129) is a very massive O + O binary that belongs to the Mon OB2 association. Previous work suggests that this system displays the Struve-Sahade effect although the ... [more ▼]

Context. Plaskett's star (HD 47 129) is a very massive O + O binary that belongs to the Mon OB2 association. Previous work suggests that this system displays the Struve-Sahade effect although the measurements of the secondary radial velocities are very difficult and give controversial results. Both components have powerful stellar winds that collide and produce a strong X-ray emission. Aims. Our aim is to study the physical parameters of this system in detail and to investigate the relation between its spectral properties and its evolutionary status. Methods. We present here analysis of an extensive set of high-resolution optical spectra of HD 47 129. We used a disentangling method to separate the individual spectra of each star. We derived a new orbital solution and discuss the spectral classification of both components. A Doppler tomography technique applied to the emission lines H alpha and He II gamma 4686 yields a Doppler map that illustrates the wind interactions in the system. Finally, an atmosphere code is used to determine the different chemical abundances of the system components and the wind parameters. Results. HD 47 129 appears to be an O8 III/I + O7.5 III binary system in a post RLOF evolutionary stage, where matter has been transferred from the primary to the secondary star. The He overabundance of the secondary supports this scenario. In addition, the N overabundance and C underabundance of the primary component confirm previous results based on X-ray spectroscopy and indicate that the primary is an evolved massive star. We also determined a new orbital solution, with M-P sin(3) i = 45.4 +/- 2.4 M-circle dot and M-S sin(3) i = 47.3 +/- 0.3 M-circle dot. Furthermore, the secondary star has a high rotational velocity (nu sin i similar to 300 km s(-1)) that deforms its surface, leading to a non-uniform distribution in effective temperature. This could explain the variations in the equivalent widths of the secondary lines with phase. We suggest that the wind of the secondary star is confined near the equatorial plane because of its high rotational velocity, affecting the ram pressure equilibrium in the wind interaction zone. [less ▲]

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See detailHigh-resolution reconstruction of atmospheric deposition of trace metals and metalloids since AD 1400 recorded by ombrotrophic peat cores in Hautes-Fagnes, Belgium
Allan, Mouhamd ULg; le roux, gael; De Vleeschouwer, François et al

in Environmental Pollution (2013), 1

The objective of our study was to determine the trace metal accumulation rates in the Misten bog, Hautes-Fagnes, Belgium, and assess these in relation to established histories of atmospheric emissions ... [more ▼]

The objective of our study was to determine the trace metal accumulation rates in the Misten bog, Hautes-Fagnes, Belgium, and assess these in relation to established histories of atmospheric emissions from anthropogenic sources. To address these aims we analyzed trace metals and metalloids (Pb, Cu, Ni, As, Sb, Cr, Co, V, Cd and Zn), as well as Pb isotopes, using XRF, Q-ICP-MS and MC-ICP-MS, respectively in two 40-cm peat sections, spanning the last 600 yr. The temporal increase of metal fluxes from the inception of the Industrial Revolution to the present varies by a factor of 5 to 50, with peak values found between AD 1930 and 1990. A cluster analysis combined with Pb isotopic composition allows the identification of the main sources of Pb and by inference of the other metals, which indicates that coal consumption and metallurgical activities were the predominant sources of pollution during the last 600 years. [less ▲]

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See detailHigh-resolution respirometry to assess muscle mitochondrial respiratory function in horses: potential applications in sport and myopathic horses
Votion, Dominique ULg; Gnaiger, Erich; Lemieux, Hélène et al

in In Proceedings: 3rd MiPsummer School, Baton Rouge, USA (2009, June)

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See detailHIGH-RESOLUTION SPECTRA OF JUPITER NORTHERN AURORAL ULTRAVIOLET EMISSION WITH THE HUBBLE-SPACE-TELESCOPE
TRAFTON, L. M.; Gérard, Jean-Claude ULg; Munhoven, Guy ULg et al

in Astrophysical Journal (1994), 421(2), 816-827

The first spectroscopic observations of planetary aurora with the HST are reported. These include spectral regions centered on the H-2 Lyman and Werner bands of a region of Jupiter's northern aurora. The ... [more ▼]

The first spectroscopic observations of planetary aurora with the HST are reported. These include spectral regions centered on the H-2 Lyman and Werner bands of a region of Jupiter's northern aurora. The observations were made with the Goddard High Resolution Spectrograph (GHRS) using the Large Science Aperture as part of a campaign to study Jupiter at the time of the Ulysses flyby. The individual rotational-vibrational bands are resolved and the observed emissions are essentially all from H-2. A rotational-vibrational temperature for H-2 of 530 +/- 100 K is derived, a value significantly less than the 850-1100 K reported for Jovian H-3(+) in the near-infrared but consistent with the temperature reported for fundamental-band quadrupole H-2 emission. Comparison with the Faint Object Camera (FOC) images shows that the observed region was not one of the hot spots of the aurora. The results are interpreted in terms of electron impact excitation of H-2 from secondary particles generated by primaries precipitating into Jupiter's atmosphere from the magnetosphere. In the region of the aurora observed, the homopause level is found to be significantly hotter but not necessarily higher than observed at nonauroral latitudes. The equatorial H-2 dayglow spectrum was also detected; its intensity was 3.2 kR or 13% of the strength of the observed auroral emission. [less ▲]

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See detailHigh-resolution spectropolarimetric observations of hot subdwarfs
Petit, P.; Van Grootel, Valérie ULg; Bagnulo, S. et al

in Leaflet - Astronomical Society of the Pacific (2012, March 01), 452

We report on high-resolution spectropolarimetric observations of the hot subdwarf stars HD 76431 and Feige 66, using the ESPaDOnS echelle spectropolarimeter at CFHT. We compute cross-correlation Stokes I ... [more ▼]

We report on high-resolution spectropolarimetric observations of the hot subdwarf stars HD 76431 and Feige 66, using the ESPaDOnS echelle spectropolarimeter at CFHT. We compute cross-correlation Stokes I and V line profiles to enhance the signal-to-noise ratio. We then average all available cross-correlation profiles of each star to further decrease the noise level. Although both targets were previously reported to host kilo-gauss magnetic fields, we do not derive any evidence of large-scale photospheric fields from our sets of observations, in spite of tight error bars on the longitudinal field of the order of 60 gauss for HD 76431 and 200 gauss for Feige 66. A new analysis of FORS1 observations of HD 76431, which provided the basis for the original claim of field detection, confirms the absence of any detectable Zeeman signature, with an error bar of about 100 gauss on the longitudinal magnetic field. [less ▲]

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See detailHigh-resolution spectroscopy of the C2 Swan 0-0 band from Comet P/Halley
Lambert, D. L.; Sheffer, Y.; Danks, A. C. et al

in Astrophysical Journal (1990), 353

High-resolution spectra of the C2 Swan system's 0-0 band from Comet P/Halley in March 1986 show that the populations of the upper state's rotational levels may be described by two rotational temperatures ... [more ▼]

High-resolution spectra of the C2 Swan system's 0-0 band from Comet P/Halley in March 1986 show that the populations of the upper state's rotational levels may be described by two rotational temperatures. The low rotational levels provide a low temperature, Trot = about 600 - 700 K. The higher levels correspond to about 3200 K. If a contribution from the 3200-K molecules is subtracted from the populations of the low-J-prime levels, the latter are characterized by Trot = about 190 K. A comparison with recent predictions for C2 molecules fluorescing in sunlight shows that the observed and predicted level populations are in good agreement for J-prime greater than about 15, but there is a sharp disagreement for the low rotational levels. [less ▲]

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